1. Field of the Invention
The present invention relates generally to air flow control rearwardly of a moving vehicle, and more particularly but not by way of limitation, to reducing air drag rearwardly of a vehicle having a rectangularly shaped rear end.
2. Description of the Prior Art
It is well known that as a vehicle, such as a conventional closed body trailer or the like, travels over a roadway, a significant amount of air drag on the vehicle results since movement of the vehicle through the atmosphere tends to create an area of lower pressure rearwardly thereof. The resulting area of highly turbulent air induces drag on the vehicle and, if the roadway is wet, dusty or covered with debris, creates a spray or a cloud thereof rearwardly of the vehicle. Such conditions can significantly restrict the rearward visibility of a person operating the vehicle, as well as the visibility of anyone following the vehicle.
Various apparatus have been proposed in the past to reduce air drag, or increase streamlining, of vehicular bodies such as conventional box shaped trailers and the like. Examples of such are shown in the following U.S. Pat. Nos.: 2,146,297, issued to Huet; 3,010,754, issued to Shumaker; and 3,960,402, issued to Keck. One other patent which may be considered relevant to the present invention is U.S. Pat. No. 2,781,226, issued to Tydon. This patent contemplates cargo vehicle bodies which can be transported over a roadway as well as through the air via an airplane while maintaining a streamlined shape for air travel. However, the Tydon patend considers air drag unimportant for highway travel.
Other means and apparatus relevant to the field of air drag reduction, but more particularly relating to vehicles having aerodynamic shapes other than those pertinent to the present invention, and means and apparatus utilized to reduce air drag near the front end of a vehicle, are disclosed in the following patents: U.S. Pat. Nos. 780,124, issued to Monnier; 1,871,396, issued to Stalker; 2,036,560, issued to Backus; 2,877,046, issued to Funk; 3,425,740, issued to Vaughm; 3,834,752, issued to Cook et al.; 3,929,369, issued to Blair; 3,945,677, issued to Servais et al.; and France Pat. No. 724,951.